Employing Pierre Bourdieu's concept of classificatory struggles and sociological literature on professions' construction of jurisdiction, this article examines the origins of the National Taxonomy of Exempt Entities (NTEE), the dominant classification system for the US nonprofit sector. Using data drawn from archival research and secondary research, I show that the establishment of the NTEE was part of a larger symbolic struggle over the proper classification of charitable foundations. Philanthropic elites and new nonprofit scholars responded to government threats to foundations by integrating them into the newly created "nonprofit sector," whose societal value—both philanthropic and economic—would be demonstrated through research on this sector. The NTEE was formed by nonprofit researchers to generate valid data that demonstrated the nonprofit sector's multiple contributions to society's well-being. Using a theoretical approach, this article extends Bourdieu's emphasis on classificatory struggles beyond the study of the construction of the characteristics of social classes to explore contestations over the proper taxonomy of organizations and sectors in society.